149557 Conferences false [["minutes", "Minutes"], ["notes", "Notes"], ["paper", "Paper"], ["poster", "Poster"], ["slides", "Slides"], ["summary", "Summary"]] Brookhaven National Laboratory (US) jd@bnl.gov 22874 chep2012@bnl.gov CHEP False New York City, NY, USA

2012-05-21T06:00:00 2012-05-25T18:00:00 2011-08-02T14:01:11 2012-06-19T20:27:46 US/Eastern Unknown mernst@bnl.gov CERN dirk.duellmann@cern.ch 481 false [["minutes", "Minutes"], ["notes", "Notes"], ["paper", "Paper"], ["poster", "Poster"], ["slides", "Slides"], ["summary", "Summary"]] Event Processing (track 2) 2 Poster SLAC National Accelerator Laboratory drandyhaas@gmail.com Atlas carlino@na.infn.it University of Edinburgh (GB) p.j.clark@ed.ac.uk CERN daniel.froidevaux@cern.ch Kimmel Center

None

Rosenthal Pavilion (10th floor) 2012-05-24T13:30:00 2012-05-24T18:15:00 04:45 We are now in a regime where we observe substantial multiple proton-proton collisions within each filled LHC bunch-crossing and also multiple filled bunch-crossings within the sensitive time window of the ATLAS detector. This will increase with increased luminosity in the near future. Including these effects in Monte Carlo simulation poses significant computing challenges. We present a description of the standard approach used by the ATLAS experiment and details of how we manage the conflicting demands of keeping the background dataset size as small as possible while minimizing the effect of background event re-use. We also present details of the methods used to minimize the memory footprint of these digitization jobs, to keep them within the grid limit, despite combining the information from thousands of simulated events at once. We also describe an alternative approach, known as Overlay. Here, the actual detector conditions are sampled from raw data using a special zero-bias trigger, and the simulated physics events are overlaid on top of this zero-bias data. This gives a realistic simulation of the detector response to physics events. The overlay simulation runs in time linear in the number of events and consumes memory proportional to the size of a single event, with small overhead. We explain the computational issues and challenges that will arise in running overlay in production mode on the grid. Finally we discuss the computational issues that may arise in the future in generating large amount of luminosity weighted zero-bias data and making it available on the grid slides doc http://indico.cern.ch/images/word.png word file ppt http://indico.cern.ch/images/powerpoint.png powerpoint file pdf http://indico.cern.ch/images/pdf_small.png pdf file odt http://indico.cern.ch/images/writer.png writer file odp http://indico.cern.ch/images/impress.png presentation file ods http://indico.cern.ch/images/calc.png spreadsheet file other http://indico.cern.ch/images/file_small.png unknown type file link http://indico.cern.ch/images/link.png link 2013-05-24 2013-05-25